Here are some tips to help reduce the energy consumption of an air conditioner in a large space

1. Get a properly sized unit. An AC that is too small will run constantly to try to cool the space. Have an HVAC professional calculate the appropriate BTU rating needed for the square footage.
2. Consider a variable speed or multi-stage unit. These can operate at lower capacities during milder days and ramp up output as needed. This reduces energy use.
3. Install a programmable thermostat. Set the AC to run less when no one is home and to increase the temperature setting overnight.
4. Use ceiling or oscillating fans to circulate the cooled air more effectively through the entire room. This allows you to raise the thermostat setting by a few degrees.
5. Make sure the air ducts are properly sealed. Leaky ducts can reduce efficiency by allowing cooled air to escape before reaching the space.
6. Add insulation to the attic and walls if lacking. This will help keep the cool air in and reduce heat gain.
7. Replace old windows with energy efficient models. Tinting films can also help reduce solar heat gain.
8. Keep the air filters clean. Dirty filters make the AC work harder to push air through. Change per the manufacturer’s recommendations.
9. Close vents and doors in unused rooms so only occupied areas get cooled.
10. Use shades and curtains to block sunlight. Keep them closed during the hottest part of the day.
11. Avoid using heat generating appliances during peak cooling hours.

With some adjustments and regular maintenance, you can maximize efficiency and reduce energy consumption from your air conditioner. A certified HVAC technician can also help optimize your system.